Table 2: Study design and results of DBPCC for NCWS diagnosis.
Results of double-blind placebo-controlled trials (DBPCC) in patients with suspected non-celiac wheat sensitivity (NCWS): study design and modality of gluten/wheat administration, duration of the trial, number of patients completing the trial and percentage of patients with confirmed NCWS (complaining of symptoms triggered with wheat/gluten and not with placebo).
| Reference | Study Design | Inclusion criteria | Mode of administration of gluten/wheat | Placebo | Duration of the trial | Number of patients completin g DBPCC | Number of patients Having symptoms triggered with gluten/wheat but not with placebo |
|---|---|---|---|---|---|---|---|
| Biesiekierski et al., 2013, Australia (ref 57) | Cross-over randomized DBPCC | Self-reported NCWS patients | Food with high (16 g/d) or low content (2 g/d) of carbohydratedepleted wheat protein | Gluten-free food with whey protein (16 g/d) | 2 week-run-in period with a low-FODMAPs diet/1 week with high or low-gluten diet or placebo/2-week washout before cross-over for 1 week | 37 | 3 (8%) |
| Carroccio et al, 2012, Italy (ref 24) | Cross-over, randomized DBPCC | IBS and selreported NCWS patients | Wheat flourcontaining capsules (13 g/d) | Xylosecontaining capsules | 2 weeks with one type of capsules/1-week washout/2 weeks with the other type of capsules | 270 | 70 (26%) |
| Zanini et al., 2015, Italy (ref 55) | Cross-over randomized DBPCC | Self-reported NCWS patients | Gluten containing flour | Gluten-free flour | 10 days with one type of flour /2-week washout/ 2 weeks with the other flour | 35 | 12 (34%) |
| Di Sabatino et al., 2015, Italy (ref 53) | Cross-over randomized DBPCC | Self-reported NCWS patients | Gluten containing capsules (4.375 g/d) | Rice starch containing capsules | 1 week with one type of capsules/1week wash-out/1week with the other type of capsules | 59 | 9 (15%) ° |
| Elli et al,, 2016, Italy (ref 54) | Cross-over randomized DBPCC | Patients with functional symptoms, including IBS and functional dyspepsia | Gluten containing capsules (5.6 g/d) | Rice starch containing capsules | 1 week with one type of capsules/1week wash-out/1week with the other type of capsules | 98 | 14 (14%) |
| Skodje GI et al., 2018, Norway (ref 58) | Cross-over randomized DBPCC | Self-reported NCWS patients | Gluten (5.7g/d), fructans (2.1g/d) concealed in muesli bars | Not reported | 1 week with one type of bars (once daily) with gluten or fructans or placebo, followed by 1-week washout | 59 | 0* |
| Overall results | 558 | 108 (19.3%) |
Of these patients, three out of 59 (5%) showed a particularly pronounced symptomatic response to gluten.
Fructans (not gluten) induced the highest symptom scores for bloating compared to placebo, but not for other NCWS-related symptoms. Notes: DBPCC, double-blind, placebo controlled challenge; IBS, irritable bowel syndrome; NCWS, non-celiac wheat sensitivity; FODMAPs, fermentable oligo-, di-, monosaccharides, and polyols.